Establishment of animal models for atopic dermatitis and induction of oral tolerance

用2,4,6-三硝基氯苯胺致敏BALB/C小鼠，然后用相同的抗原每隔2天在原致敏部位重复诱导，共24天。为了研究接触性超敏反应急性期和慢性期皮肤细胞因子环境的差异，采用RT-PCR技术评估了2,4,6-三硝基氯苯应用于急性和慢性病变后的顺序细胞因子动力学。结果，在急性病变中观察到th1型细胞因子（IL-2, ifn - γ） mRNA水平升高，而在慢性病变中观察到th2型细胞因子（IL-4, IL-10） mRNA水平明显上调。对皮下注射镍致敏的BALB/C小鼠进行的类似研究也表明，反复注射镍会导致Th1为主的反应向Th2为主的反应转变。反复诱导前口服镍可抑制皮炎的发展。我们使用RT-PCR技术证明了重复诱导位点的th2型反应。随后，用2,4,6-三硝基氯苯致敏BALB/C小鼠，然后用相同的抗原每隔2天在原致敏部位重复诱导，连续24天。利用原位杂交技术，我们检测了ifn - γ mRNA和IL-10mRNA表达的时间过程和定位。在急性病变中，我们发现真皮T细胞中ifn - γ mRNA的表达在几小时到12小时之间增加。10 ~ 24小时真皮T细胞IL-10mRNA表达上调。在慢性病变中，IL-10mRNA的表达在3-24小时时浸润到表皮和真皮的T细胞中。

BALB/C mice were sensitized with 2,4,6-trinitro-chlorobenz ine, and then were repeatedly elicited on the original sensitized site with the same antigen at 2-day intervals for 24 days. To investigate the differences in the cutaneous cytokine milieu between the acute and chronic phases of contact hypersensitivity, sequential cytokine dynamics after 2,4,6-trinitro-chlorobenzine application were assessed in the acute vs chronic lesions, using RT-PCR technique. As a result, increased mRNA levels for Th1-type cytokines (IL-2, IFN-gamma) were observed in the acute lesions, whereas those for Th2-type cytokines (IL-4, IL-10) were markedly up-regulated in the chronic lesions.Similar study with BALB/C mice sensitized by subcutaneous nickel injection also showed that repeated applications of nickel gave rise to a shift from Th1 to Th2 dominated responses. Oral administration of nickel prior to repeated elicitation suppressed development of dermatitis. We demonstrated Th2-type responses in the repeatedly elicited sites, using RT-PCR technique.Subsequently, BALB/C mice were sensitized with 2,4,6-trinitro-chlorobenzine and then were repeatedly elicited on the original sensitized site with the same antigen at 2-day intervals for 24 days. Using in-situ hybridization technique, we examined time course and localization of expression for IFN-gamma mRNA and IL-10mRNA.In the acute lesions, we demonstrated increased expression for IFN-gamma mRNA on T cells in the dermis between several and 12 hours. Expression of IL-10mRNA on T cells in the dermis was up-regulated between 10 and 24 hours. In the chronic lesions, expression of IL-10mRNA was observed on infiltrating T cells into epidermis and dermis at 3-24 hours.